Note: Descriptions are shown in the official language in which they were submitted.
CA 02616465 2008-01-24
True translation of PCT/EP2006/006753 as filed on July 11, 2006
Polling system for a moved machine component
Description
The invention relates to a polling system for a moved machine
component. Such a polling system is known, for example, from DE 103
07 565 Al. In this prior art, pressure spaces to which pressure is applied
in a rotating power chuck are monitored using pressure sensors. The
pressure sensors are electrically powered from rechargeable batteries
that rotate along with the chuck. A stationary, non-rotating receiver is
allocated to the pressure sensors. This receiver is connected to a unit for
evaluating the signals received from the pressure sensor.
In this prior art, the pressure is measured by the pressure sensor, which
requires electrical power and the signals generated by the pressure
sensor are transmitted to the receiver by radio. Electrical power is
required both to power the sensor during pressure measurement and to
emit the radio waves. Because the electrical power from the rechargeable
batteries is limited, the operating duration is relatively short.
The object of this invention is to provide a polling system for a moved
machine component that requires relatively little electrical energy and
has relatively long maintenance intervals due to its low energy
consumption.
This object is achieved by a polling system for a moved machine
component, comprising a first polling subunit that is to be disposed at the
machine component end and is provided with at least one switch that
operates without power in a certain state of the machine component or in
a certain position of a part of the machine component, a radio
CA 02616465 2008-01-24
2
transmitter unit that evaluates the switching modes of the switch and
transmits the evaluated switching signals with digital radio switching
signals, and an electric power source for supplying the radio transmitter
unit. The inventive polling system further comprises a radio receiver unit
that is stationary relative to the polling subunit and is used for receiving
and evaluating, forwarding and/or displaying the signals received from
the radio transmitter unit.
The invention has the advantage over prior art, that a switch is used that
operates without power and does not consume any electrical power itself.
The switch is operated in a certain state of the movable machine
component or in a certain position of a part of the machine component.
In the inventive polling system, electrical power is only required to
evaluate the switching signals, to convert the switching signals into
digital radio switching signals and to transmit the digital radio switching
signals. The power source of the polling subunit at the machine
component end therefore only supplies power to the radio transmitter
unit. As the signals of the switching modes transmitted are not analog
signals but already evaluated, digitized radio switching signals, the
energy consumption of the transmitter unit is reduced. Transmission of
digital signals can be performed relatively fast as compared with analog
signals and therefore with energy savings, that is, in the range below one
millisecond.
In the inventive polling system, the radio receiver unit receives and
evaluates, forwards and/or displays the digital signals of the radio
transmitter unit. In particular, the radio transmitter unit can comprise an
interface with the machine control that controls the moved machine
component.
CA 02616465 2008-01-24
3
To reduce the energy consumption of the radio transmitter unit still
further, the invention can include a radio transmitter unit that is
structured such that the radio switching signals are only transmitted
when the switching mode of the switch changes. In this case, electrical
power is only required to transmit radio signals when the switching mode
has actually changed.
In a further advantageous embodiment of the invention, the radio
transmitter unit is structured such that it monitors the status of the
power source and transmits relevant energy check signals and that the
receive unit evaluates, forwards and/or displays these signals. This
permits monitoring the status of the power source. It can be detected if
the power source is too weak and/or if there is a fault in the power
source. If necessary, protective measures can be taken, such as ending
the motion of the machine component.
According to the invention, the radio transmitter unit can also be
structured such that the radio contact check signals are transmitted and
that the receiver unit evaluates, forwards and/or displays these signals.
In this way, it is possible to check whether adequate radio contact exists.
If the radio contact check signals are not received, an alarm may be
generated, forwarded and/or displayed, for example.
The power source check signals and/or the radio contact check signals
are used, in particular, to increase the functional reliability of the polling
system. This enables reliable and timely detection of a polling system
failure.
To keep the consumption of electrical power low according to the
invention, the energy check signals and/or the radio contact check
signals can be polled and/or transmitted at regular intervals. In
CA 02616465 2008-01-24
4
particular, the time intervals can be set depending on the safety
relevance of the moved machine component. If the power source used is
a battery, it may be sufficient to transmit the power source check signal
once every few seconds. The power source check signal and/or the radio
contact check signal is advantageously transmitted as a digital signal by
the radio transmitter unit.
In a further embodiment of the invention, the radio transmitter unit can
be switched into an operating mode, a setting mode and a storage mode.
The operating mode is used during normal operation of the machine
component and is especially energy-saving. The setting mode is used for
setting and calibrating the polling system, with the possibility of using
optical signal transmitters in addition to the radio signals to represent
optically the transmission of the radio switching signals or the reception
of the radio switching signals. In setting mode, higher energy
consumption is therefore accepted. In the third mode (storage mode) the
power source is electrically disconnected from the radio transmitter unit,
so that no consumption of power can occur. Provision of these three
modes can therefore further optimize power consumption.
Switching between the modes can be performed by means of a
contactless magnetic switching element. The provision of a contactless
magnetic switching element has the advantage that no corrosion occurs if
the radio transmitter unit is stored for a long time and the functional
reliability of the polling system is increased. The magnetic element could
be a magnetic pin, for example, with different positions of the magnetic
pin setting different modes.
According to the invention, the power source may advantageously be a
battery or an autonomous power generator that generates electrical
CA 02616465 2008-01-24
power from available external energy. The power generator may be solar
cells.
According to the invention, the switches used may be momentary-contact
switches, maintained-contact switches, pressure switches or magnetic
proximity switches. The decisive property of the switches is that they
function without electrical power.
The object of the invention stated above is achieved by a machine
component that can be disposed such that it can rotate about an axis of
rotation and that has the form of a power chuck with a chuck body
carrying clamping jaws in the radial direction. This power chuck
comprises an inventive polling system whose polling subunit is located in
the chuck body. Such a power chuck has the advantage that, by means
of the polling system, for example, the clamping pressure with which the
clamping jaws hold a workpiece and/or the position of the clamping jaws
can be polled and transmitted to the radio receiver unit with relatively
little electrical power.
In this case, it is advantageous if the switch operating without power is a
pressure switch for monitoring the clamping pressure state of the
clamping pressure equipment and/or the clamping position of the
clamping jaws. Such a pressure switch is, for example, operated by the
prevailing clamping pressure and can, for example, be set depending on
the intended clamping pressure.
An inventive power chuck can be characterized in that the radio
transmitter unit comprises an antenna that protrudes in the axial
direction out of the surface of the chuck body that extends
perpendicularly to the axis of rotation. This ensures that optimum radio
contact can be maintained between the radio transmitter unit in the
CA 02616465 2008-01-24
6
chuck body, or rather the associated antenna, and the radio receiver
unit.
The antenna can have the form of a helical spring and protrude along an,
in particular, curved line out of the surface of the chuck body that
extends perpendicular to the axis of rotation. An antenna thus
constituted has proven very advantageous in practice because, due to
the helical form of the antenna and the protrusion of the antenna out of
the surface of the chuck body that extends perpendicularly to the axis of
rotation, radio signals can reliably be transmitted optimally with low
transmission power.
According to a further embodiment of the invention, the radio transmitter
unit together with the antenna and power source can be disposed
completely within a plastic casting. This protects the radio transmitter
unit from external influences, such as cutting emulsions and/or chips.
The object of the invention stated above is also solved by a machine
component that can be moved by means of a handling system in the
form of an automation component that comprises an inventive polling
system, the polling subunit being disposed in or on the automation
component and the radio receiver unit being stationary with respect to
the automation component. The automation component is therefore
moved in three dimensions using a handling system, for example, using a
robot arm. By means of the inventive polling system that can be disposed
in or on the automation component, certain positions and/or certain
states of the automation component or parts of the automation
component can be polled.
As automation components, in particular, gripping or clamping fixtures
can be used that comprise a base body and jaws disposed in the base
CA 02616465 2008-01-24
7
body such that they can move. With the inventive polling system, for
example, the positions of the jaws can be polled and communicated to
the radio receiver unit. The automation component may also be a
swiveling unit that has a swiveling element located in a base body such
that it can rotate. With the polling module, it is possible, for example, to
poll and communicate the position of the swiveling element. Moreover,
an inventive automation component can be a quick-change system. In
this case, the invention can be used to poll whether the tool has been
changed. Moreover, the automation component used may be collision or
overload protection that, for example, effectively protects a robot or
robot manipulator against damage due to collision or overload conditions.
In this context, the inventive polling system can acquire or communicate
the occurrence of a collision or overload condition. According to the
invention, an automation component can also be a linear drive and/or a
lift drive. In this case, the inventive polling system is used to poll and
communicate the position of the lift element moved by the drive.
According to the invention automation components can other than those
mentioned can also include an inventive polling system.
Further details and advantages of the invention can be seen from the
following description in which the embodiments shown in the figures are
described and explained in more detail.
Content of the figures:
Figure 1 Various inventive automation components;
Figure 2 A radio transmitter unit with two switches of an automation
component according to Figure 1;
CA 02616465 2008-01-24
8
Figure 3 A second radio transmitter unit for a power chuck;
Figure 4 A power chuck incorporating a radio transmitter unit
according to Figure 3; and
Figure 5 A radio receiver unit for a radio transmitter unit according to
Figure 2 or Figure 3.
Figure 1 shows various automation components. Firstly, a swiveling unit
is shown that comprises a base housing 12 and a swiveling element 14.
Secondly, a parallel gripper 16 is shown that comprises a base housing
18 and two jaws 20 that can be moved further together and further apart
in the base housing and gripper fingers 22 on the jaws. The third
automation component is a swivel gripper unit 24 shown in Figure 1 that
has a base housing 26 and two gripper fingers 28 that can be swiveled
further together or further apart. The automation components shown in
Figure 1 can, for example, be disposed such that they can be moved in
three dimensions by means of handling systems. The machine
component parts 10, 16, 24 can comprise polling systems for polling the
orientation or position of the moved components 14, 22, 28.
Such a polling system comprises a polling subunit at the automation
component end that can be disposed, for example, in the case of the
swivel unit 10, on the base housing 12; in the case of the parallel gripper
16, on the base housing 18; and in the case of the swivel gripper 24, on
the base housing 26. Such a polling subunit is shown in Figure 2 and
identified with the reference number 30. The polling subunit 30
comprises two switches 32 that operate without power, which are
connected to a radio transmitter unit 36 by means of the electrically
conducting cables 34. The switches 32 can, for example, be constituted
as magnetic proximity switches in the form of Reed switches that operate
CA 02616465 2008-01-24
9
when a ferromagnetic element or permanent magnet enters their
detection range. Such switches do not require a power supply.
The radio transmitter unit 36 evaluates the switching signals of the
switches 32 and transmits digital radio switching signals, for example, in
the form of radio telegrams to a radio receiver unit 38 shown in Figure 2.
The polling subunit 30 shown in Figure 2 also comprises a power source
(not depicted) in the form of a battery. A power generator, such as solar
cells, can be used instead of or in addition to the battery.
Because switches 32 do not require electrical power and previously
evaluated, digital switching signals are transmitted, the radio transmitter
unit requires relatively little electrical power. For example, if one digital
radio signal per second is transmitted by the radio transmitter unit, the
life of the conventional batteries that are available today may be five to
ten years. Such a long battery life results, in particular, when the
duration of the transmitted digital radio switching signals is shorter than
one millisecond.
Figure 3 shows a second embodiment of a polling subunit 40 to be
disposed in a moved machine component in the form of a power chuck
44 with a chuck body 42 shown in Figure 4 such that it can rotate about
an axis of rotation 46. The chuck body 42 comprises jaw guides in the
radial direction for clamping jaws 50 that can be moved in the radial
direction. The clamping jaws 50 can hold workpieces centered for
machining by turning.
As shown in Figure 3, the polling subunit 40 comprises a switch 52 that
operates without power, in particular, a pressure switch for monitoring
the clamping pressure state of clamping pressure equipment with which
the clamping pressure of the jaws 50 is produced. Moreover, the polling
CA 02616465 2008-01-24
subunit 40 comprises a radio transmitted unit 54 for evaluation of the
switching modes of the pressure switch 52 and for transmission of the
evaluated switching signals by means of digital radio signals. The radio
transmitter unit 54 comprises an antenna 56 constituted as a helical
spring that protrudes along the curved line 58 out of a surface 60 of the
chuck body 42 that extends perpendicularly to axis of rotation. The
curved line 58 along which the antenna 56 extends can, in particular, be
clearly seen in Figure 3. The surrounding edge 62 facing the antenna 56
is substantially flush with the surface 42 when the polling subunit 40 is
built into the chuck body 42. Such a disposition has the advantage that
radio signals can be transmitted optimally with comparatively low power
consumption through the antenna 56 that is protruding from the surface
42 even when the power chuck 44 rotates rapidly.
In Figure 4, the polling subunit 40 is built into the power chuck 44, or
rather into its chuck body 42. For this purpose, the chuck body 42
includes a recess matching the external dimensions of the polling subunit
40. As already explained, when built in, the antenna 56 protrudes in the
axial direction out of the surface that extends perpendicular to the axis of
rotation 46.
As can also be seen from Figure 3, the polling subunit 40 comprises a
power source in the form of a battery 62. The battery 62, the radio
transmitter unit 54 and the antenna 56 are completely encased in a
plastic casting. When built in, the pressure switch 52 that is connected
via a cable to the radio transmitter unit 54 is in or on the pressure space
of the clamping pressure equipment.
As already explained, Figure 5 shows a radio receiver unit 38 that is
stationary and comprises an antenna 64 with which the digital radio
signals are received from the radio transmitter unit 36 according to
CA 02616465 2008-01-24
11
Figure 2 and/or from the radio transmitter unit 40 according to Figure 4.
The radio transmitter unit 38 has an interface 66 for connection with a
machine control, in particular, with the machine control that controls
automation components 10, 16, 14 according to Figure 1 and/or the
power chuck 44 according to Figure 4 transmitted digital radio switching
signals can also be polled with the radio receiver unit 38.
The radio transmitter units shown in the figures can be structured to
monitor the status of the power sources and transmit relevant power
source check signals. If the power source check signals fall below a
certain value, this can be detected, displayed and/or forwarded to the
machine control by the radio receiver unit 38.
Moreover, the radio transmitter units 30, 44 are constituted such that
they transmit radio contact check signals that are received by the radio
receiver unit 38. If regularly transmitted radio contact check signals are
not received, this can result in an alarm.
The radio receiver unit 38 has various indicator lamps, that is, a power
source indicator lamp 68 of the radio transmitter unit 40, a radio contact
check lamp 70 and two switching contact indicator lamps 72, to check
the switching modes of the switches 32, 52. Moreover, an indicator lamp
74 is provided for the power supply of the radio receiver unit 38.
